Re: [RFC PATCH 6/7] migration/multifd: Move payload storage out of the channel parameters

[Peter Xu]

On Thu, Jul 18, 2024 at 04:39:00PM -0300, Fabiano Rosas wrote:
> v2 is ready, but unfortunately this approach doesn't work. When client A
> takes the payload, it fills it with it's data, which may include
> allocating memory. MultiFDPages_t does that for the offset. This means
> we need a round of free/malloc at every packet sent. For every client
> and every allocation they decide to do.

Shouldn't be a blocker?  E.g. one option is:

    /* Allocate both the pages + offset[] */
    MultiFDPages_t *pages = g_malloc0(sizeof(MultiFDPages_t) +
                                      sizeof(ram_addr_t) * n, 1);
    pages->allocated = n;
    pages->offset = &pages[1];

Or.. we can also make offset[] dynamic size, if that looks less tricky:

typedef struct {
    /* number of used pages */
    uint32_t num;
    /* number of normal pages */
    uint32_t normal_num;
    /* number of allocated pages */
    uint32_t allocated;
    RAMBlock *block;
    /* offset of each page */
    ram_addr_t offset[0];
} MultiFDPages_t;

-- 
Peter Xu